A solid state imaging device is used for imaging radiation such as X-rays, and is also used for, for example, medical purposes such as dental purposes. Such a solid state imaging device includes a photodetecting section including M×N pixel portions P1,1 to PM,N two-dimensionally arrayed in M rows and N columns, each including a photodiode, a scintillator layer provided so as to cover the photodetecting section, a signal readout section which outputs voltage values corresponding to amounts of charges generated in the photodiodes included in the pixel portions of the photodetecting section, and a controlling section which controls operations of the photodetecting section and signal readout section, etc. In the solid state imaging device, the photodetecting section, the signal readout section, and the controlling section, etc., may be formed on a semiconductor substrate.
In this solid state imaging device, scintillation light is generated in response to incidence of radiation on the scintillator layer, and in response to incidence of the scintillation light on the photo diode included in any of the pixel portions of the photodetecting section, charges are generated in this photodiode. Then, voltage values corresponding to amounts of charges generated in photodiodes included in the respective pixel portions of the photodetecting section are output from the signal readout section. Thus, a radiation image is obtained.
In such a solid state imaging device, when radiation and scintillation light transmitted through the scintillator layer are made incident on a region (for example, regions of the signal readout section and controlling section, a field region for wire bonding, etc., hereinafter, these regions will be referred to as “peripheral regions”) other than the photodetecting section, charges may be generated at this incidence position. Then, the charges generated in the peripheral region may move from the generation position and be accumulated in a junction capacitance portion of a photodiode included in any of the pixel portion of the photodetecting section. In this case, charges to be output from this pixel portion of the photodetecting section include not only charges generated in the photodiode in this pixel portion but also charges generated in the peripheral region as noise. Therefore, an accurate radiation image cannot be obtained.
An invention intended to solve this problem is disclosed in Patent Document 1. The solid state imaging device disclosed in this document includes a shielding member which blocks incidence of radiation on the peripheral region. This shielding member has an opening above the photodetecting section, and can allow radiation to be made incident on the scintillator layer provided on the photodetecting section.    Patent Document 1: Japanese Published Unexamined Patent Application No. 2004-177217